U.S. patent application number 09/819268 was filed with the patent office on 2001-10-04 for navigating method and device for an autonomus vehicle.
This patent application is currently assigned to Kanazawa Institute of Technology. Invention is credited to Kihara, Yusuke, Nakano, Yoshiyuki.
Application Number | 20010027360 09/819268 |
Document ID | / |
Family ID | 18644361 |
Filed Date | 2001-10-04 |
United States Patent
Application |
20010027360 |
Kind Code |
A1 |
Nakano, Yoshiyuki ; et
al. |
October 4, 2001 |
Navigating method and device for an autonomus vehicle
Abstract
The present invention relates to navigation of an autonomous
vehicle capable of autonomously tracking a route toward a
destination. The present invention provides a system comprising the
steps of forming a route for an autonomous vehicle with a plurality
of information storing elements placed at specific locations in
line along a passageway, each beacon storing its own location
information on the route, mounting an information retrieving
section on the autonomous vehicle so that as the vehicle travels,
the information retrieving section comes in sufficient proximity to
the information storing elements in sequence, transmitting radio
waves between the information retrieving section and information
storing element, supplying, through the transmission of the radio
wave, electricity from the vehicle to the information storing
element to activate it, retrieving, by the information retrieving
section, location information from the information storing element
that indicates the vehicle's present position, and controlling a
moving direction of the vehicle based on this vehicle's position
information.
Inventors: |
Nakano, Yoshiyuki;
(Kanazawa-shi, JP) ; Kihara, Yusuke; (Tokyo,
JP) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Kanazawa Institute of
Technology
|
Family ID: |
18644361 |
Appl. No.: |
09/819268 |
Filed: |
March 28, 2001 |
Current U.S.
Class: |
701/23 ; 340/994;
701/533 |
Current CPC
Class: |
G01C 21/26 20130101;
G05D 1/0261 20130101 |
Class at
Publication: |
701/23 ; 701/201;
340/994 |
International
Class: |
G01C 022/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2000 |
JP |
2000-136418 |
Claims
1. A navigating method for an autonomous vehicle, comprising the
steps of: providing a route for the vehicle, formed with a
plurality of information storing elements in line along passageways
on which the vehicle travels, each of said information storing
elements storing in advance its own location information on the
route, mounting an information retrieving section on the vehicle so
that as the vehicle travels, said information retrieving section
will come sufficiently close to said plurality of information
storing elements in sequence; transmitting radio waves between said
information retrieving section and an information storing element;
supplying, through transmission of the radio wave, electricity from
the vehicle to said information storing element placed along the
route to activate said information storing element; retrieving, by
said information retrieving section of the vehicle, the location
information stored in said information storing element that
indicates the present position of the vehicle; and controlling a
moving direction of the vehicle based on said position information
to guide the vehicle along the route to a destination.
2. A navigating method for navigating an autonomous vehicle, the
method comprising the steps of: providing a beacon line formed with
a plurality of route beacons placed in line along passageways, each
beacon comprising: a memory storing its own location information on
the route of a vehicle; an antenna for transmitting and receiving
radio waves; a power circuit for converting a radio wave received
by said antenna and supplying it as electricity; and a
transmitting/receiving circuit, including said antenna, for
receiving a radio wave, retrieving, powered by said power circuit,
said beacon location information from said memory and transmitting
said beacon location information by said antenna in the form of
radio wave, said beacons being placed at specific locations
corresponding to their respective location information, on said
vehicle having driving wheels and steering means for controlling
its moving direction, mounting: a transmitting/receiving circuit,
including an antenna for transmitting transmitting/receiving radio
waves, for transmitting a radio wave toward said route beacon and
for receiving a radio wave containing the location information
thereof, thus obtaining the present position information of the
vehicle therefrom; and a power source for operating said
transmitting/receiving circuit, said driving wheels and said
steering means for controlling a moving direction of the vehicle,
providing the vehicle further with a computer, in which information
indicating locations of said route beacons to a destination is
stored in advance, for executing computation, including comparing
said retrieved vehicle's position information with said information
indicating locations of the route beacons; controlling said
steering means to control the moving direction based on a
computation result; supplying, through transmission of the radio
wave from said transmitting/receiving circuit of the vehicle,
electricity from said vehicle to said beacons in sequence as the
vehicle travels autonomously, thereby retrieving the stored
location information from the memory of said route beacon;
transmitting a radio wave containing said location information to
the transmitting/receiving circuit of the vehicle in sequence;
receiving, by said transmitting/receiving circuit of the vehicle,
said radio wave containing the location information and obtaining
the vehicle's present position information therefrom; executing
computation, by said computer, including comparing the vehicle's
present position information with said information indicating the
locations of the route beacons; and controlling a moving direction
of the vehicle based on said computation result to track the line
of said route beacons, thereby guiding the autonomous vehicle along
the route to the destination.
3. A navigating method for an autonomous vehicle recited in claim
2, wherein the vehicle has a single mobile transmitting/receiving
circuit, including an antenna for receiving a radio wave from a
route beacon, and said antenna is rotated to the right and left in
the moving direction of the vehicle, thereby detecting said radio
wave from said route beacon.
4. A navigating method for an autonomous vehicle recited in claim
2, wherein there are two lines, each formed with the beacons,
placed in parallel with each other, said vehicle has a single
mobile transmitting/receiving circuit, including an antenna for
receiving a radio wave from a route beacon, and based on a phase of
said single transmitting/receiving circuit in which said radio wave
from a route beacon is received, the vehicle's present position and
its moving direction are detected.
5. A navigating method for navigating an autonomous vehicle, the
method comprising the steps of: providing a beacon line formed with
a plurality of route beacons placed in line along passageways, each
beacon comprising: a memory storing its own location information on
the route of a vehicle; an antenna for transmitting and receiving
radio waves; a power circuit for converting a radio wave received
by said antenna and supplying it as electricity; and a
transmitting/receiving circuit, including said antenna, for
receiving a radio wave, retrieving, powered by said power circuit,
said beacon location information from said memory and transmitting
said beacon location information by said antenna in the form of
radio wave, said beacons being placed at specific locations
corresponding to their respective location information, on said
vehicle having driving wheels and steering means for controlling
its moving direction, mounting: a transmitting/receiving circuit,
including an antenna for transmitting transmitting/receiving radio
waves, for transmitting a radio wave toward said route beacon and
for receiving a radio wave containing the location information
thereof, thus obtaining the present position information of the
vehicle therefrom; and a power source for operating said
transmitting/receiving circuit, said driving wheels and said
steering means for controlling a moving direction of the vehicle,
providing the vehicle further with a computer, in which information
indicating locations of said route beacons to a destination is
stored in advance, for executing computation, including comparing
said retrieved vehicle's position information with said information
indicating locations of the route beacons; controlling said
steering means to control the moving direction based on a
computation result; supplying, through transmission of the radio
wave from said transmitting/receiving circuit of the vehicle,
electricity from said vehicle to said beacons in sequence as the
vehicle travels autonomously, thereby retrieving the stored
location information from the memory of said route beacon;
transmitting a radio wave containing said location information to
the transmitting/receiving circuit of the vehicle in sequence;
receiving, by said transmitting/receiving circuit of the vehicle,
said radio wave containing the location information and obtaining
the vehicle's present position information therefrom; executing
computation, by said computer, including comparing the vehicle's
present position information with said information indicating the
locations of the route beacons; and controlling a moving direction
of the vehicle based on said computation result to track the line
of said route beacons, thereby guiding the autonomous vehicle along
the route to the destination, wherein there are a plurality of
transmitting/receiving circuits, each circuit including an antenna
for receiving a radio wave from a route beacon, and based on phases
of respective said transmitting/receiving circuits, in which said
radio wave from a route beacon is received, said vehicle's present
position and its moving direction are detected.
6. A navigating method for an autonomous vehicle recited in claim
5, wherein there is a single line formed with route beacons, the
vehicle has two transmitting/receiving circuits, each circuit
including an antenna for receiving a radio wave from a route
beacon, and, based on phases of said two transmitting/receiving
circuits, in which said radio wave from each route beacon is
received, said vehicle's present position and its moving direction
are detected.
7. A navigating method for an autonomous vehicle recited in claim
5, wherein different oscillation frequencies are assigned to said
plurality of transmitting/receiving circuits respectively, each
circuit including an antenna for receiving a radio wave from a
route beacon, so that radio wave interference between said
plurality of transmitting/receiving circuits is prevented.
8. A navigating method for an autonomous vehicle recited in claim
5, wherein said plurality of transmitting/receiving circuits are
operated on a timeshare basis to prohibit a simultaneous operation
of said transmitting/receiving circuits, so that radio wave
interference between said plurality of transmitting/receiving
circuits is prevented.
9. A navigating device for an autonomous vehicle, comprising: a
plurality of route beacons, each beacon having: a memory storing
its own location information in reference to a route of the
vehicle; an antenna for transmitting and receiving radio waves; a
power circuit for converting said radio wave received by said
antenna and supplying it as electricity; and a
transmitting/receiving circuit, including an antenna, for receiving
a radio wave, retrieving, powered by said power circuit, said
beacon location information from said memory, and transmitting said
beacon location information by said antenna in the form of radio
wave; a route beacon line formed with said route beacons placed at
specific locations corresponding to their respective location
information; a vehicle having driving wheels and steering means for
controlling its moving direction; a mobile transmitting/receiving
circuit, including a radio wave transmitting/receiving antenna, for
transmitting and receiving radio waves toward and from said route
beacons and retrieving said beacon location information so as to
obtain vehicle's present position information therefrom; a power
source for operating said mobile transmitting/receiving circuit,
said driving wheels and said steering means; and a computer, in
which information indicating locations of the beacons to a
destination is stored, for executing computation, including
comparing said obtained vehicle's position information with said
information indicating locations of the route beacons, thereby
controlling a moving direction of said steering means, said
navigating device for the autonomous vehicle wherein said mobile
transmitting/receiving circuit and said power source are mounted
thereon.
10. A navigating device for an autonomous vehicle recited in claim
9, wherein there is a single mobile transmitting/receiving circuit
on which an antenna is supported in such a manner that it rotates
to the right and left in the moving direction of the vehicle.
11. A navigating device for an autonomous vehicle recited in claim
9, wherein there are two beacon lines placed in parallel with each
other, each line formed with said route beacons, and there is a
single mobile transmitting/receiving circuit.
12. A navigating device for an autonomous vehicle, comprising: a
plurality of route beacons, each beacon having: a memory storing
its own location information in reference to a route of the
vehicle; an antenna for transmitting and receiving radio waves; a
power circuit for converting said radio wave received by said
antenna and supplying it as electricity; and a
transmitting/receiving circuit, including an antenna, for receiving
a radio wave, retrieving, powered by said power circuit, said
beacon location information from said memory, and transmitting said
beacon location information by said antenna in the form of radio
wave; a route beacon line formed with said route beacons placed at
specific locations corresponding to their respective location
information; a vehicle having driving wheels and steering means for
controlling its moving direction; a mobile transmitting/receiving
circuit, including a radio wave transmitting/receiving antenna, for
transmitting and receiving radio waves toward and from said route
beacons and retrieving said beacon location information so as to
obtain vehicle's present position information therefrom; a power
source for operating said mobile transmitting/receiving circuit,
said driving wheels and said steering means; and a computer, in
which information indicating locations of the beacons to a
destination is stored, for executing computation, including
comparing said obtained vehicle's position information with said
information indicating locations of the route beacons, thereby
controlling a moving direction of said steering means, said
navigating device for the autonomous vehicle wherein said mobile
transmitting/receiving circuit and said power source are mounted
thereon, wherein there are a plurality of mobile
transmitting/receiving circuits.
13. A navigating device for an autonomous vehicle recited in claim
12, wherein there is a single beacon line formed with said route
beacons; and there are two mobile transmitting/receiving
circuits.
14. A navigating device recited in claim 12, wherein different
oscillation frequencies are assigned to said plurality of mobile
transmitting/receiving circuits respectively.
15. A navigating device recited in claim 12, wherein said plurality
of transmitting/receiving circuits are operated on a time-share
basis to prohibit a simultaneous operation of said
transmitting/receiving circuits.
16. An autonomous vehicle having a navigating device comprising: a
mobile transmitting/receiving circuit for transmitting a radio wave
toward a plurality of route beacons, each route beacon comprising:
a memory storing location information indicating its own location
on a passageway; an antenna for transmitting and receiving radio
waves; a power circuit for converting the radio wave received by
said antenna into electricity and supplying it as electricity; and
a transmitting/receiving circuit for receiving a radio wave and
retrieving, powered by said power circuit, said location
information from said memory and transmitting it by said antenna in
the form of radio wave, said mobile transmitting/receiving circuit
for receiving said radio wave from said route beacon and obtaining
the vehicle's present position information therefrom; a power
source required for operating said mobile transmitting/receiving
circuit, driving wheels and steering means of the vehicle for
controlling a moving direction of the vehicle; and a computer, in
which information indicating locations of said route beacons on the
passageway to a destination is stored, for executing computation,
including comparing said vehicle's present position information
with said information indicating locations of the route beacons,
thereby controlling said steering means.
17. An autonomous vehicle provided with a navigating device recited
in claim 16, wherein said navigating device is provided with a
single mobile transmitting/receiving circuit, and an antenna of
said mobile transmitting/receiving circuit is supported in such a
manner that said antenna rotates to the right and left in the
moving direction of the vehicle.
18. An autonomous vehicle having a navigating device comprising: a
mobile transmitting/receiving circuit for transmitting a radio wave
toward a plurality of route beacons, each route beacon comprising:
a memory storing location information indicating its own location
on a passageway; an antenna for transmitting and receiving radio
waves; a power circuit for converting the radio wave received by
said antenna into electricity and supplying it as electricity; and
a transmitting/receiving circuit for receiving a radio wave and
retrieving, powered by said power circuit, said location
information from said memory and transmitting it by said antenna in
the form of radio wave, said mobile transmitting/receiving circuit
for receiving said radio wave from said route beacon and obtaining
the vehicle's present position information therefrom; a power
source required for operating said mobile transmitting/receiving
circuit, driving wheels and steering means of the vehicle for
controlling a moving direction of the vehicle; and a computer, in
which information indicating locations of said route beacons on the
passageway to a destination is stored, for executing computation,
including comparing said vehicle's present position information
with said information indicating locations of the route beacons,
thereby controlling said steering means, wherein said navigating
device is provided with a plurality of said mobile
transmitting/receiving circuits.
19. An autonomous vehicle provided with a navigating device recited
in claim 18, wherein different oscillation frequencies are assigned
to said plurality of mobile transmitting/receiving circuits
respectively.
20. An autonomous vehicle provided with a navigating device recited
in claim 18, wherein said plurality of transmitting/receiving
circuits are operated on a time-share basis to prohibit a
simultaneous operation of said transmitting/receiving circuits.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method for navigating an
autonomous vehicle that enables the autonomous vehicle to track a
route accurately along passageways to a predetermined destination
and to travel autonomously along the route. The present invention
also relates to a device for navigating an autonomous vehicle using
the aforementioned navigating method, and an autonomous vehicle
provided with the navigating device using the navigating
method.
[0002] Needs for so-called autonomous vehicles have been recognized
in various industrial fields. The autonomous vehicle includes a
self-motored vehicle having a power source, guided by sensors, for
autonomously delivering goods to designated locations along routes
on indoor or outdoor passageways, and a mobile carriage as part of
robotic systems. However, the following requirements must be
satisfied to navigate such an autonomous vehicle:
[0003] (1) The vehicle should by itself be able to measure and
recognize its current position;
[0004] (2) The vehicle should by itself be able to track a route
accurately along passageways leading itself to a destination;
and
[0005] (3) The vehicle should by itself be able to autonomously
guide itself along the found route.
[0006] Following conventional navigating methods are known for
navigating autonomous vehicles:
[0007] (a) The vehicle is mounted with a camera, or an ultrasonic
sensor, for visually observing and analyzing the surroundings of
the vehicle and determines, based on the analysis result, a route
to be followed that leads itself to a destination (the visual-image
recognition method).
[0008] (b) Lines of light-reflecting tape are applied along
passageways. The vehicle is mounted with a light-emitting device
for lighting the light-reflecting tape and a light-detecting device
for detecting the light reflection of the light-reflecting tape,
thereby enabling the vehicle to track the light-reflecting tape.
The light-reflecting tapes may be laid at intervals along
passageways. As the vehicle travels, the vehicle counts, by a
counter mounted on the vehicle, the number of tapes it has passed,
and calculates the distance that the vehicle has traveled (the tape
method).
[0009] (c) Cables generating an electromagnetic wave are laid
continuously along passageways. An electromagnetic wave receiver is
mounted on the vehicle for tracking the cables (the electromagnetic
wave/cable method).
[0010] (d) Rail tracks are laid along passageways. The vehicle
travels along the rail tracks (the rail-track method).
[0011] However, the visual-image recognition method has a problem
that it requires a high-quality image processing device for
analyzing complex backgrounds and contours of the vehicle's
surroundings. The tape method has a different problem that the
tapes may become undetectable over years of use because of quality
changes the tapes sustain due, for instance, to accumulation of
dirt. The electromagnetic wave/cable method would cost
significantly for laying cables. The rail track method also costs
heavily for laying rails, and moreover, the rail tracks likely
become obstacles for other traffics.
[0012] On the other hand, another method, using an RFID (Radio
Frequency Identification Device), has been known. The RFID is a
device that uses electromagnetic short wave (SW) to be exchanged
between an information storing element and an information
retrieving section as they come in proximity to each other, thereby
supplying electricity from the information retrieving section to
the information storing element and activating it, which transfers
information (such as location data) stored therein to the
information retrieving section where the data is then
recognized.
[0013] One example of the FRID method described above is disclosed
in the Official Gazette of Laid-open Japanese Patent Application
No. Sho 62-501671. The structure of the RFID in this application is
similar to the structure shown in a block circuit diagram of FIG.
7. In FIG. 7, a numeral 71 indicates an information storing element
comprising a memory 711 storing a variety of information (for
example, location data indicating its location along a route, which
data is also required in the present invention), a power circuit
712, a control circuit 713, a modular circuit 714, an antenna coil
(antenna) 715, etc. The section comprising the control circuit 713
and the modular circuit 714 may be regarded as a
transmitting/receiving circuit 11a. A numeral 72 indicates an
information retrieving section comprising an oscillator circuit
721, a demodulating circuit 722, an antenna coil (antenna) 723,
etc. The section consisting of the oscillator circuit 721 and the
demodulating circuit 722 may be regarded as another
transmitting/receiving circuit 11b. Although the information
storing element 71 and the information retrieving section 72 are
illustrated in the drawing at a distance therebetween, their
respective antenna coils 715 and 723 come in proximity to each
other in use. A numeral 73 indicates an information processing unit
(computer) for processing information (data) which the information
retrieving section 72 retrieved from the memory 711.
[0014] In order for the information retrieving section 72 to become
able to retrieve information stored in the memory 711 of the
information storing element 71, electricity has to be supplied from
the information retrieving section 72 to the information storing
element 71. For this purpose, the antenna coils 715 and 723 are
first brought sufficiently close to each other, and the oscillator
circuit 721 of the information retrieving section 72 is activated
to oscillate, thus transmitting high-frequency electric current to
the antenna coil 723. The antenna coil 723, in response, generates
SW toward the antenna coil 715 of the information storing element
71. As a result, the antenna coils 723 and 715 become
electro-magnetically connected, and thus the high-frequency
electric current is induced through the antenna coil 715. After
converted at the power circuit 712, the electric current is
supplied to the information storing element 71 in the form of
electricity. This electricity activates the control circuit 713 to
retrieve information (for example, location data) stored in the
memory 711. Such information is then converted (modulated) by the
modulating circuit 714 into high frequency electric current
representing the information and transmitted from the antenna coil
715 toward the antenna coil 723 in the form of radio wave. The
radio wave received by the antenna coil 723 of the information
retrieving section 72 is then demodulated by the demodulating
circuit 722 into the original information (such as location data)
retrieved from the memory 711. The demodulated information is then
sent to the computer 73 where the retrieved information is compared
with a group of information (indicating, for instance, locations of
information storing elements along passageways) stored in advance
in the computer, and processed so that the information from the
memory 711 is recognized and used for creating control signals.
BRIEF SUMMARY OF THE INVENTION
[0015] The present invention relates to navigation of an autonomous
vehicle and solves the problems of the aforementioned conventional
navigating methods. It is an object of the present invention to
reduce construction costs of navigation system facilities while
providing long-term reliability to the navigating system.
[0016] It is another object of the present invention that when a
vehicle is about to run off a route, it can detect such a status
quickly and prevent the vehicle's deviation from the route, and
that it can also prevent navigation errors due to interferences of
navigation radio waves.
[0017] According to the present invention, an autonomous vehicle is
navigated along a route, using the functional concepts of the Radio
Frequency Identification Device (RFID). The navigating method of
the present invention comprising the steps of:
[0018] providing a route for a vehicle, formed with a plurality of
elements, which correspond to the information storing element 71 of
the RFID, in line along passageways on which the vehicle travels,
each of the information storing element having a memory 711 storing
in advance its own location information on the route;
[0019] mounting a component, which corresponds to the information
retrieving section 72 of the RFID, on the vehicle so that as the
vehicle travels, the information retrieving section 72 will come
sufficiently close to the plurality of information storing elements
71 in sequence;
[0020] transmitting radio waves between the information retrieving
section 72 and an information storing element 71;
[0021] supplying, through transmission of the radio wave,
electricity from the vehicle to the information storing element 71
placed along the route to activating the information storing
element 71;
[0022] retrieving, by the information retrieving section 72 of the
vehicle, the location information stored in the information storing
element that indicates the present position of the vehicle; and
[0023] controlling a moving direction of the vehicle based on the
position information to guide the vehicle along the route to a
destination.
[0024] Another form of preferred embodiments of the present
invention is a navigating method for navigating an autonomous
vehicle, the method comprising the steps of:
[0025] providing a beacon line formed with a plurality of route
beacons placed in line along a passageway, each beacon comprising:
a memory storing its own location information on the route of a
vehicle; an antenna for transmitting and receiving radio waves; a
power circuit for converting the radio wave received by the antenna
and supplying it as electricity; and a transmitting/receiving
circuit, including the antenna, for receiving the radio wave,
retrieving, powered by the power circuit, the beacon location
information from the memory and transmitting the beacon location
information by the antenna in the form of radio wave, the beacons
being placed at specific locations corresponding to their
respective location information,
[0026] on the vehicle having driving wheels and steering means for
controlling its moving direction, mounting: a
transmitting/receiving circuit, including an antenna for
transmitting/receiving radio waves, for transmitting a radio wave
toward the route beacon and for receiving a radio wave containing
the location information thereof, thus obtaining the present
position information of the vehicle therefrom; and a power source
for operating the transmitting/receiving circuit, the driving
wheels and the steering means for controlling a moving direction of
the vehicle,
[0027] providing the vehicle further with a computer, in which
information indicating locations of the route beacons to a
destination is stored in advance, for executing computation,
including comparing the retrieved vehicle's position information
with the information indicating locations of the route beacons;
[0028] controlling the steering means to control the moving
direction based on a computation result;
[0029] supplying, through the transmission of the radio wave from
the transmitting/receiving circuit of the vehicle, electricity from
the vehicle to the beacons in sequence as the vehicle travels
autonomously, thereby retrieving stored location information from
the memory of the route beacon;
[0030] transmitting a radio wave containing the location
information to the transmitting/receiving circuit of the vehicle in
sequence;
[0031] receiving, by the transmitting/receiving circuit of the
vehicle, the radio wave containing the location information and
obtaining the vehicle's present position information therefrom;
[0032] executing computation, by the computer, including comparing
the vehicle's present position information with the information
indicating locations of the route beacons; and
[0033] controlling a moving direction of the vehicle based on the
computation result to track the line of the route beacons, thereby
guiding the autonomous vehicle along the route to the
destination.
[0034] A second preferred embodiment form of the present invention
is a navigating device for navigating an autonomous vehicle,
comprising:
[0035] a plurality of route beacons, each beacon having: a memory
storing its own location information in reference to a route of the
vehicle; an antenna for transmitting and receiving radio waves; a
power circuit for converting the radio wave received by the antenna
and supplying it as electricity; and a transmitting/receiving
circuit, including an antenna, for receiving a radio wave,
retrieving, powered by the power circuit, the beacon location
information from the memory, and transmitting the beacon location
information by the antenna in the form of radio wave,
[0036] a route beacon line formed with the route beacons placed at
specific locations corresponding to their respective location
information;
[0037] a vehicle having driving wheels and steering means for
controlling its moving direction;
[0038] a mobile transmitting/receiving circuit, including a radio
wave transmitting/receiving antenna, for transmitting and receiving
radio waves toward and from the route beacons and retrieving the
beacon location information so as to obtain vehicle's present
position information therefrom;
[0039] a power source for operating the mobile
transmitting/receiving circuit, the driving wheels and the steering
means; and
[0040] a computer, in which information indicating locations of the
route beacons to a destination is stored, for executing
computation, including comparing the obtained vehicle's position
information with the information indicating locations of the route
beacons, thereby controlling a moving direction of the steering
means, the navigating device for the autonomous vehicle wherein the
mobile transmitting/receiving circuit and the power source are
mounted thereon.
[0041] A third preferred embodiment form of the present invention
is an autonomous vehicle having a navigating device comprising:
[0042] a mobile transmitting/receiving circuit for transmitting a
radio wave toward a plurality of route beacons, each route beacon
comprising: a memory storing location information indicating its
own location on a passageway; an antenna for transmitting and
receiving radio waves; a power circuit for converting the radio
wave received by the antenna into electricity and supplying it as
power; and a transmitting/receiving circuit for receiving a radio
wave, retrieving, powered by the power circuit, the location
information from the memory and transmitting it by the antenna in
the form of radio wave, the mobile transmitting/receiving circuit
for receiving the radio wave from the route beacon and obtaining
the vehicle's present position information therefrom;
[0043] a power source required for operating the mobile
transmitting/receiving circuit, driving wheels and steering means
of the vehicle for controlling a moving direction of the vehicle;
and
[0044] a computer, in which information indicating locations of the
route beacons on the passageway to a destination is stored, for
executing computation, including comparing the vehicle's present
position information with the information indicating locations of
the route beacons, thereby controlling the steering means.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0045] FIG. 1 is a summarized plane view showing an autonomous
vehicle equipped with a first preferred embodiment of a navigating
device according the present invention.
[0046] FIG. 2 is a side view of the autonomous vehicle shown in
FIG. 1.
[0047] FIG. 3 is a diagram explaining the navigating procedures
operated by the navigating device of the autonomous vehicle shown
in FIGS. 1, 2.
[0048] FIG. 4 is a diagram explaining the navigating procedures
operated by a navigating device according to a second preferred
embodiment of the present invention.
[0049] FIG. 5 is a diagram explaining the navigating procedures
operated by a navigating device according to a third preferred
embodiment of the present invention.
[0050] FIG. 6 is a diagram explaining the navigating procedures
operated by a navigating device according to a forth preferred
embodiment of the present invention.
[0051] FIG. 7 is a diagram showing the structure of RFID
circuits.
[0052] The foregoing and other objects, aspects and advantages will
be better understood from the following detailed description of
preferred embodiments of the invention with reference to the
attached drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0053] The present invention will be described below in reference
with drawings showing preferred embodiments. FIGS. 1, 2 are plane
view and cross-sectional side view respectively, showing an
autonomous vehicle according to the present invention. In FIGS. 1,
2, numerals A1, A2, A3, . . . An, . . . indicate route beacons that
are placed at regular intervals along indoor or outdoor passageways
leading to a destination. The route beacons are adhered onto a
surface R of the passageway or laid underground. These route
beacons A1, A2, A3, . . . An, . . . are constructed in a similar
manner that the information storing element 71 of the RFID, as
described in reference with FIG. 7, is constructed. Each beacon is
provided with an integrated circuit comprising: a memory 711; a
power circuit 712; a transmitting/receiving circuit 11a (control
circuit 713 and modular circuit 714); and an antenna coil 715.
Also, the memory 711 of each of the beacons A1, A2, A3, . . . An, .
. . stores its own location information (location data) indicating
its position (on the route).
[0054] In FIGS. 1, 2, a numeral 1 indicates a carriage mounted with
driving wheels 2, driven wheels 3, a motor 4 for driving the
driving wheels, a motor drive 5 for controlling the motor 4, a
steering mechanism 6 for controlling the moving direction of the
carriage 1, a controller 7 for controlling the steering mechanism
6, and a power source 8.
[0055] In addition, the carriage 1 is further equipped with: a
carriage navigating device B; a computer C; and a radio
communications unit 9 for communicating with a host computer, that
is not mounted on the carriage 1. The computer C stores information
indicating locations of the route beacons on the route to the
destination. The carriage navigating device B corresponds to the
information retrieving section 72 of the RFID, that was described
in reference with FIG. 7. The carriage navigating device B
comprises an antenna section 10 and a transmitting/receiving
circuit 11. The antenna section 10 consists of two SW antenna coils
(antennas) 101, 102 that are placed adjacent to each other and
positioned left and right in the moving direction of the carriage
1. The transmitting/receiving circuit 11 consists of two mobile
transmitting/receiving circuits 111, 112 connected respectively to
the SW antennas 101, 102.
[0056] As the carriage 1 travels along the route on the passageway,
the antenna section 10 (the SW antenna coils 101, 102) comes in
proximity to an antenna coil 715 of each of the route beacons A1,
A2, A3, . . . An, . . . in sequence. At each encounter, radio waves
are transmitted and received between the microwave antenna coils
101, 102 and the antenna coil 715, thereby supplying electricity
from the carriage navigating device B to each route beacon An (71)
in sequence, and the mobile transmitting/receiving circuits 111,
112 retrieve location information stored in the memory 711 of the
route beacon An (71), i.e., the present position information of the
carriage 1 (mobile unit). The computer C then executes computation,
including comparing this retrieved location information with its
own location information indicating locations of the route beacons
and uses a computation result to control the motor drive 5, the
motor 4, the controller 7, and the steering mechanism 6, thereby
enabling the carriage 1 to track the route formed with the route
beacons A1, A2, A3, . . . , An, . . . along the passageway, thereby
autonomously navigating the carriage 1 to the destination. The
power source 8 is for providing electricity to various components
and devices including the motor 4, the carriage navigating device
B, the computer C and the radio communications unit 9, as well as
providing electricity to each route beacon An via the antenna coils
101, 102, (723), 715.
[0057] FIG. 3 shows the process in which the antenna coils 101, 102
of the antenna section 10 mounted on the carriage 1 retrieve the
location information stored in the memory 711 of a route beacon An
(71) via its antenna coil 715. In this process, each of the antenna
coils 101, 102 of the antenna section 10 is capable of retrieving
information within a limited range defined by its sensitivity. For
example, they can retrieve location information stored in route
beacons A1 and A2 within their combined information-retrievable
ranges (i.e., the radio wave receivable ranges) 101s, 102s, as
shown in FIG. 3. The antenna coils 101, 102 are closely placed side
by side with a small distance therebetween so that the
information-retrievable range of the antenna section 10 consists of
the information-retrievable ranges 101s and 102s separately covered
by the antenna coils 101 and 102, respectively, and an over-wrapped
information-retrievable range 103s covered by both antenna coils
101, 102. Apparently, location information of other route beacons,
that are located outside these information-retrievable ranges 101s,
102s and 103s, cannot be retrieved by the antenna section 10.
[0058] The route beacons A1, A2, A3, . . . An, . . . are placed at
respective locations on the route along the passageway to the
destination. When a route beacon An receives a radio wave
transmitted from the antenna coils 101, 102 of the carriage
navigation device B mounted on the carriage 1, a power source
circuit 712 of the route beacon An converts the radio wave into
electricity. The electricity activates a control circuit 713 that
reads out the location information of the route beacon An stored in
the memory 711 and transmits the location information from an
antenna coil 715 in the form of radio wave toward the carriage
navigating device B. If the transmitted radio wave is detected in
the radio wave receivable ranges (the information-retrievable
ranges) of the antenna coils 101, 102 of the carriage navigating
device B, the location information of the route beacon An is
retrieved by the antenna coils 101, 102. This location information
is then computed by the computer C and the computation result is
used to correctly navigate the carriage 1 to the destination.
[0059] When the carriage 1 is passing directly above a beacon line
N on which the route beacons A1, A2, A3, . . . An . . . are placed,
each route beacon An should come in the over-wrapped information
retrievable range 103s covered by both antenna coils 101, 102 so
that both antenna coils 101, 102 simultaneously read the location
information of the same route beacon An.
[0060] When the moving direction of the carriage 1 runs off
leftward from the beacon line N on which the route beacons A1, A2,
A3, . . . An . . . are placed, the route beacon An comes into the
information retrievable range 102s covered only by the antenna coil
102, and thus the location information of the route beacon An is
retrieved only by the antenna coil 102.
[0061] On the other hand, when the moving direction of the carriage
1 runs off rightward from the beacon line N on which the route
beacons A1, A2, A3 . . . An . . . are placed, the route beacon An
comes into the information retrievable range 101s covered only by
the antenna coil 101, and thus the location information of the
route beacon An is retrieved only by the antenna coil 101.
[0062] Thus, a deviation of the traveling direction of the carriage
1 from a designated route can be detected based on the information
retrievable range in which the beacon location information is
retrieved. The controller 7 controls the steering mechanism 6 to
steer the carriage 1 back to the correct course in order to
correctly and autonomously guide the carriage 1 to the destination.
The location information of the destination and information
indicating the locations of all route beacons on a route to the
destination may be stored in advance in the computer C mounted on
the carriage 1. As the carriage 1 travels, the location information
of each of the route beacons A1, A2, A3, . . . An, . . . , is read
out and compared with the computer C's information indicating
locations of the route beacons in sequence, thereby enabling the
carriage 1 to track a line of the route beacons and thus
autonomously navigating itself to the destination.
[0063] In the preferred embodiment described above, since the two
antenna coils 101, 102 are placed adjacent to each other, one
receives radio wave transmitted from the other. Therefore, the
antenna coils 101, 102 may not be able to correctly read the
location information of a route beacon An because of disturbance of
the adjacent electric fields caused by the radio waves interfering
with each other. This problem can be solved by assigning different
oscillation frequencies to the antenna coils. The interference
between the radio waves may also be prevented by operating the
mobile transmitting/receiving circuits 111, 112 on a time-share
basis to prohibit a simultaneous operation of the mobile
transmitting/receiving circuits 111, 112.
[0064] FIG. 4 shows a carriage navigating section of the navigating
device for an autonomous vehicle according to a second preferred
embodiment of the present invention. In this embodiment, the
carriage navigating device B shown in FIGS. 1 through 3 is provided
with, in addition to the antenna coils 101, 102 and the mobile
transmitting/receiving circuits 111, 112, a third antenna coil 104
located between the antenna coils 101, 102 and a third mobile
transmitting/receiving circuit (not shown in the drawing) connected
to the third antenna coil 104. Therefore, as shown in FIG. 4, the
antenna coils 101, 102, 104 have their respective information
retrievable ranges (radio wave receivable ranges) 101s, 102s, 104s.
Therefore, when the carriage 1 is traveling directly above the
route beacon line N on which the route beacons A1, A2, A3, . . .
An, . . . are placed, the location information of a route beacon An
is retrieved by the additional center antenna coil 104. If the
moving direction of the carriage 1 runs off leftward from the route
beacon line N on which the route beacons A1, A2, A3, . . . An, . .
. are placed, the location information of a route beacon An is
retrieved by the antenna coil 102 located on the right side in the
moving direction of the carriage. On the other hand, if the moving
direction of the carriage 1 runs off rightward from the route
beacon line N on which the route beacons A1, A2, A3, . . . An, . .
. are placed, the location information of a route beacon An is
retrieved by the antenna coil 101 on the left side in the moving
direction of the carriage. Therefore, depending on which of the
three antenna coils 101, 102, 104 retrieve the location information
of the route beacon An, a deviation of the carriage 1 from the
designated route can be detected. Accordingly, the controller 7
controls the steering mechanism 6 to steers the carriage 1 back to
the correct course and thus correctly and autonomously navigate the
carriage 1 to the destination.
[0065] FIG. 5 shows a carriage navigating section of the navigating
device for an autonomous vehicle according to a third preferred
embodiment of the present invention. The carriage navigating device
B shown in FIGS. 1 through 3 is provided with a single antenna coil
101 and a transmitter/receiver (not shown in the drawing) connected
to the antenna. As shown by an arrow Q, the antenna coil 101
rotates to the right and left in the moving direction of the
carriage 1 to retrieve the location information of route beacons
A1, A2, A3, . . . An . . . that form a route beacon line N.
Therefore, when the moving direction of the carriage 1 runs off
rightward or leftward from the route beacon line N on which the
route beacons A1, A2, A3, . . . An . . . are placed, the location
information of a route beacon An is retrieved by the antenna coil
101 when it rotates to the left, or to the right. The deviation of
the carriage 1 from the designated route is thus detected.
[0066] The controller 7 operates the steering mechanism 6 to steer
the carriage back to the correct course to correctly and
autonomously navigate the carriage 1 to the destination.
[0067] FIG. 6 shows a carriage navigating section of the navigating
device for an autonomous vehicle according to a forth preferred
embodiment of the present invention. In this embodiment, more than
one beacon line formed with route beacons A1, A2, A3, . . . An, . .
. , each beacon storing its own location information, are placed in
parallel with each other (in FIG. 6, two lines L, M are shown)
along a passageway. A single antenna coil 101 retrieves the
location information simultaneously from the two lines of route
beacons A1, A2, A3, . . . An . . . . When the carriage 1 is
traveling, tracing both route beacon lines L, M of the route
beacons A1, A2, A3, . . . An . . . , the antenna coil 101 retrieves
the location information of route beacons from both beacon lines L,
M. However, when the moving direction of the carriage 1 runs off
the route beacon lines L, M of the route beacons A1, A2, A3, . . .
An . . . , the antenna coil 101 moves to the place shown by
numerals 101', 101" in FIG. 6, and fails to retrieve the location
information from either beacon lines L or M.
[0068] Therefore, based on the number of beacon lines from which
the antenna coil 101 can retrieve the location information, a
deviation of the carriage 1 from the passageway route can be
detected. The deviation can be corrected by the controller 7
controlling the direction navigating mechanism 6 to steer the
carriage 1 back to the correct course and thus correctly and
autonomously navigate the carriage 1 to the destination.
[0069] As it is clear from the preferred embodiments described
above, according to the navigating method for an autonomous
vehicle, the navigating device and an autonomous vehicle with the
navigating device of the present invention, various merits are
obtained. For example, this navigating method doesn't involve
complex image processing or image analysis technologies and doesn't
require fixed navigating cables or tracks to be laid down
throughout the passageways. Therefore, the cost for building
infrastructures can be substantially reduced. Moreover, because the
present invention doesn't use component materials that deteriorate
quickly over years, such as tapes, it is possible to maintain a
highly reliable autonomous navigation operation for a long time. In
addition, by using the concept of the RFID in route beacons,
circuits for retrieving beacon location information are
automatically activated only when the vehicle is traveling by.
Therefore, an energy loss in the navigation facility during
stand-by periods can be significantly reduced.
[0070] While the invention has been described in terms of preferred
embodiment, those skilled in the art will recognize that the
invention can be practiced with modifications within the spirit and
scope of the appended claims.
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